This invention relates to a device for transdermal administration of tolterodine, optionally encompassing salts, prodrugs and metabolites thereof, to the use of tolterodine, optionally encompassing salts, prodrugs and metabolites thereof, for the manufacturing of a medicament to be administered transdermally for achieving an effect against overactive bladder, and to methods of treating overactive bladder by transdermal administration of tolterodine, optionally encompassing salts, prodrugs and metabolites thereof.
Tolterodine is an effective and safe compound for treatment of overactive bladder. The synthesis of tolterodine and its utility for the treatment of overactive bladder is disclosed in U.S. Pat. No. 5,382,600 (Pharmacia and Upjohn AB). An optimal efficacy/side effect profile is obtained at an oral dosage of 1 or 2 mg twice daily. The high potency (and thereby low clinically effective serum concentrations) and the relatively short half-life (about 2 hours in the majority of the population, i.e. in extensive metabolisers, EMs) makes tolterodine a possible candidate for a patch formulation. Further properties supporting the feasibility of the patch principle are that the overactive bladder is a syndrome that might benefit of a flat serum concentration profile and that antimuscarinic compounds are not known to cause tolerance.
Tolterodine has a molecular weight of 325.0 and 475.6 as the tartrate salt. The enantiomeric purity is  greater than 99%. The pKa value is 9.87 and the solubility in water is about 11 mg/ml (room temperature). The partition coefficient (Log P) between n-octanol and phosphate buffer at pH 7.32 is 1.83. 
Tolterodine PNU-200583
N,N-dilso-propyl-3xe2x80x2-(2-hydroxy-5-methylphenyl)-3-phenylpropanamine.
The major metabolic pathway for the metabolism of tolterodine is mediated by cytochrome P450 2D6 leading to the formation of DD 01, (R)-N,N-diisopropyl-3-(2-hydroxy-5-hydroxymethylphenyl)-3-phenylpropanamine. DD 01 metabolite (also denoted 5-HM) has a similar pharmacological profile as tolterodinexe2x80x94see Nilvebrant L, Gillberg P-G, Sparf B. xe2x80x9cAntimuscarinic potency and bladder selectivity of PNU-200577, a major metabolite of tolterodine.xe2x80x9d Pharmacol. Toxicol. (1997) 81: 195-207. For the similarity to tolterodine in pharmacological profile, see Brynne N, Dalen P, Alvan G, Bertilsson L and Gabrielsson J, Clin Pharmacol Ther 1998 (63): 529-39. A minor proportion of the population (the poor metabolisers, PMs) is devoid of the 2D6 isoenzyme and these subjects will show higher tolterodine concentrations but not measurable DD 01 levels.
The differences in tolterodine pharmacokinetic profile in EMs and PMs are not reflected in the clinical response, since the exposure to the sum of unbound tolterodine and DD 01 is similar in the two groups. The same oral dosage regimen can therefore be applied irrespective of phenotype. The transdermal concept is based on the same premise.
The present invention encompasses transdermal administration of tolterodine as R-isomer, S-isomer or as a racemic mixture.
Above-mentioned U.S. Pat. No. 5,382,600 does not disclose transdermal administration of tolterodine.
WO 98/03067 discloses the S-isomer of tolterodine. It claims transdermal administration of said S-isomer for treating urinary voiding disorders. It explicitly excludes transdermal administration of the R-isomer or of a racemic mixture. Anyhow WO 98/03067 only shows utility of the oral dosage form of said S-isomer. The transdermal administration thereof is just suggested, as are the parenteral, vaginal and aerosol routes, without any showing of utility.
WO 93/23025 and WO 96/23492 disclose transdermal administration of oxobutynin and of (S)-oxybutynin or (S)-desethyloxobutynin respectively for treating neurogenic bladder disorders. It should be noted that according to WO 93/23025 an enhancer is required in order to administer oxobutynin transdermally. Oxobutynin has a chemical structure being totally different from the one of tolterodine. WO 95/10270 discloses transdermal administration of S-terodiline for treating urinary incontinence. WO 96/27375 discloses transdermal administration of dextromethorphan or dextrorphan for treating urinary incontinence. WO 97/25984 discloses transdermal administration of a nitric oxide synthase substrate for treating urinary incontinence symptoms. WO 98/00141 discloses transdermal administration of enantiomerically enriched (S)-trihexyphenidyl for treating urinary incontinence. Anyhow none of the above substances have any similarities with tolterodine.
Hence the present invention, as further described below, is both new and inventive over prior art.
A transdermal formulation with tolterodine as active ingredient will provide an alternative to the tablet formulation for the oral route. The possibility exists that due to the more constant serum concentrations during a dosage interval, side effects in comparison to immediate release tablets, may be further reduced, while clinical efficacy is maintained.
The transdermal delivery route avoids the risk for dose dumping with extended release oral forms of administration. Moreover, patient compliance will be increased as
elderly people and children may have difficulties in swallowing oral dosage forms
patients can visually observe that they are taking their medication (contrary to not remembering whether you swallowed your tablet)
once-a-day administration is possible
several-days administration is possible with one patch.
Overall, these effects increase convenience and compliance for patients.
Accordingly, a first object of the present invention is to provide a device for transdermal administration of tolterodine, optionally encompassing salts, prodrugs and metabolites thereof, for achieving an effect against overactive bladder (encompassing detrusor instability, detrusor hyperreflexia, frequency, urgency and urge incontinence). The administration can be to a human being or to an animal. The administration may be performed without the use of an enhancer.
A second object of the invention is to provide use of a compound having an effect against overactive bladder, comprising tolterodine for the manufacture of a composition to be administered transdermally for treating overactive bladder or symptoms associated with this condition: i.e. urgency, frequency, nocturia and urge incontinence.
A third object of the invention is to provide a method of treating diseases, in humans or animals, which are treatable with antinuscarinic agents, by administering tolterodine transdermally.
Other objects of the invention will become apparent to one skilled in the art, and still other objects will become apparent hereinafter.
The present invention relates to transdermal administration of tolterodine, optionally encompassing salts, prodrugs and metabolites thereof for achieving an effect against overactive bladder. This effect is primarily achieved through the systemic effect of tolterodine. Anyhow other actions are not excluded.